Wormhole Attack

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Computer Science and Engineering Department
Indian Institute Of Technology, Bombay
Wormhole Attack in Wireless Ad-hoc Network
CS 649 : Cryptography and Network Security - I
By :
Group No : 03
Group Members :
1. Jeet Patani : 10305001
2. Ankit Shah : 10305013
3. Dhaval Manvar : 10305021
4. Swapnil Shah
: 10305063
5. Nimit Kalaria : 10305904
Wormhole Attack in Wireless Ad-hoc Network
Group No:3
Use of wireless networks grows rapidly now days. Ad-hoc networks are widely used now days. However, due to absence of infrastructures, ad-hoc networks are vulnerable to number of attacks. Securing this ad-hoc network is a major concern. Here we are going to illustrate a particularly severe attack in wireless ad-hoc network called wormhole attack and present a detailed study of it, its causes, effects it can have and remedies and ways to overcome it.

Wormhole Attack in Wireless Ad-hoc Network
Group No:3
Wormhole attack operates in two phase. In the first phase, malicious nodes(attacker node), called wormhole nodes, try to lure legitimate nodes to send data to other nodes via them.They do so by convincing legitimate nodes that sending data via a path through them causes a benefit to them(may be with respect to time, distance etc.) Now once a route is established through it ,in the second phase,wormhole nodes could exploit the data in variety of ways. It can start dropping packets via it, or modify it or even just view data and get useful information or can even monitor data.In this way it can turn out to be very dangerous.We now examine various ways in which malicious node convinces legitimate path to route packets via it (i.e. launh attack) and later see remedies for it. 2

Wormhole Attack Modes
Wormhole attack can be launched using many ways. Following are some of modes. • Encapsulation
• Out-of-Band Channel
• High Power Transmission
• Packet Relay
• Protocol Deviations
Now we will see each mode in detail.
In this mode of attack, malicious node(X) near source node hears the RREQ packet. It tunnels it to the second malicious node(X’) near destination node. For tunneling, X encapsulates the packet with source as X and destination as X’. X’ then rebroadcasts the RREQ packets. So now neighbours of X’ will dorp all further legitimate requests that arrive on legitimate multihop paths. As a result of this, route between source and destination will always pass from X and X’. Thus now they have formed wormhole between them. This prevents nodes of network from discovering legitimate paths that are more than two hopes away.

As show in the Figure 2.1.1 below, all nodes will be aware about the path passing from Malicious Node 1 and Malicious Node 2.
Wormhole Attack in Wireless Ad-hoc Network
Group No:3
Figure: 2.1.1 Wormhole using Encapsulation
• There is a smaller probability of a RREQ being discarded than other RREQs that are repeatedly received by intermediate nodes.
• A RREQ packet arriving at destination does not hold intermediate nodes as hops, and then it appears to have passed through min number of hops. Disadvantages
• Resources and time consumption in packet encapsulation and decapsulation. 2.2
Wormhole using Out-of-Band Channel
This mode uses as Out of band channel. This channel can be established by long range wireless link or a direct wired link. It is more difficult then the previous mode of attack since a specialized hardware is required. Consider the scenario shown in Figure 2.2.1 below. Here direct wired link is used as out of band channel. Here all the routes from source to destination wil pass from Malicious Node 1 and Malicious Node 2 as shown in the diagram as it provides path with minimum number of hops. 3

Wormhole Attack in Wireless Ad-hoc Network
Group No:3
Figure: 2.2.1 Wormhole using Out of Band Channel
• Control packet arrives faster since there is no processing from intermediate nodes. • It...
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